Method of electroplating and varying the resistance of a wafer

Abstract

An electroplating apparatus is provided with a metal target and a device for supporting a semiconductor wafer (or other workpiece) in an electroplating solution. The target (anode) may be located relatively far from the wafer surface (cathode) at the beginning of the plating process, until a sufficient amount of metal is plated. When an initial amount of metal is built up on the wafer surface, the target may be moved closer to the wafer for faster processing. The movement of the target may be controlled automatically according to one or more process parameters.

1 - 50 . (canceled)  
     
     
         51 . A method of electroplating a wafer, said method comprising: 
 changing the resistance of said wafer while applying an electric potential across a first distance; and    subsequently, applying an electric potential to said wafer across a second distance, said first distance being greater than said second distance.    
     
     
         52 . The method of  claim 51 , wherein the resistance of said wafer is reduced during said step of changing the resistance of said wafer.  
     
     
         53 . The method of  claim 51 , further comprising partially forming at least one layer on said wafer to decrease said resistance of said wafer.  
     
     
         54 . The method of  claim 53 , wherein the step of decreasing the resistance of said wafer further comprises moving said wafer from said first distance to said second distance.  
     
     
         55 . A method of controlling the rate at which metal is deposited on a wafer surface, said method comprising: 
 placing a wafer in an electroplating solution at a predetermined distance from first and second electrical contacts;    forming a metal layer on at least a portion of said wafer, wherein said step of forming a metal layer changes the resistance of the wafer surface; and    subsequently, moving an electrode and/or said wafer in response to the change in said resistance of the wafer's surface.    
     
     
         56 . A method of electroplating a surface of a semiconductor wafer, said wafer comprising the steps of: 
 using an electrode to electroplate an initial amount of material on said surface of said semiconductor wafer such that the variability of the resistance of said surface relative to a radial position of said wafer is reduced; and    subsequently, changing the distance between said electrode and said surface of said semiconductor wafer.    
     
     
         57 . A method of varying the resistance of a wafer, said method comprising: 
 placing said wafer in an electroplating solution at a first distance from a first anode;    providing a second anode at a second distance from said wafer, wherein said first distance is greater than said second distance.    
     
     
         58 . The method of  claim 57 , further comprising applying a first electric potential from said first anode to said wafer, wherein said wafer has a first resistance.  
     
     
         59 . The method of  claim 58 , wherein said step of applying a first electric potential forms an initial amount of metal on said wafer at a first deposition rate changing said first resistance of said wafer to a second resistance.  
     
     
         60 . The method of  claim 59 , wherein subsequently, after said first resistance of said wafer changes to said second resistance, a second electric potential is applied to said wafer from said second anode.  
     
     
         61 . The method of  claim 60 , wherein said step of applying a second electric potential results in an additional amount of metal formed on said wafer.